The present invention relates to a method and apparatus for angle coding in a projectile which can be guided by means of a data transmission device, can be launched from a smooth-walled tube and begins to rotate immediately after leaving the launching tube.
Such trackable projectiles which begin to rotate only after leaving the launching tube, require exact information as to their instantaneous roll position for carrying out guidance maneuvers. For guiding the projectiles, for instance, guide beams with polarized light are used which allow detection of the roll position. This method, however, has the disadvantage that in the position information obtainable from the light beams, an ambiguity is always still present as to whether the projectile is, relatively in the 0.degree. or the 180.degree. position. For this reason, a fixed precoding of the roll position in the projectile is necessary. This, however, requires a large amount of technical means for the signal processing in the projectile if additional information regarding the roll position must further be processed. Practically, this could be accomplished by evaluating guide beam information by a stern receiver of the projectile, but this is hardly possible due to the heavy smoke development at the start. Otherwise, it is necessary to insert the projectile into the launching tube with a given roll orientation prior to the launching. This is not feasible in practice, however. The above mentioned disadvantages are to be avoided by means of the present invention.